MoS2–CoS2 heteronanosheet arrays coated on porous carbon microtube textile for overall water splitting

Abstract

Designing low-cost but efficient non-noble-metal bifunctional electrocatalysts is necessary for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in the process of water splitting. Herein, we report a self-standing bifunctional electrode by coating MoS 2 –CoS 2 heteronanosheet arrays on porous carbon microtube textile (MoS 2 –CoS 2 @PCMT) for alkaline overall water splitting. The abundant MoS 2 –CoS 2 heterogeneous interfaces with electronic interaction (confirmed by X-ray photoelectron spectroscopy) can optimize the adsorption free energies for HER and OER intermediates (supported by the theoretical calculation), making MoS 2 –CoS 2 @PCMT achieve lower overpotentials for HER and OER than Pt/C@PCMT and RuO 2 @PCMT at higher current density. In addition, the freestanding structure of PCMT and the tight adhesion with MoS 2 –CoS 2 heteronanosheets facilitate MoS 2 –CoS 2 @PCMT a long-term durability. As a result, the MoS 2 –CoS 2 @PCMT || MoS 2 –CoS 2 @PCMT couple show a relatively low water-splitting voltage of 1.59 V at 10 mA cm −2 , and demonstrate lower cell voltage than the benchmark Pt/C@PCMT || RuO 2 @PCMT couple at higher current density. This work gives prominence to the design of self-standing electrode structure and coupling of transition metal dichalcogenides to improve the performance of electrocatalysts for water splitting. • MoS 2 –CoS 2 heteronanosheet arrays are grown on PCMT for overall water splitting. • Porous carbon microtube textile (PCMT) is used as the freestanding substrate. • XPS analysis and DFT calculations confirmed the interface electronic interaction. • The abundant interfaces can regulate the adsorption free energies of intermediates. • MoS 2 –CoS 2 @PCMT shows excellent activity and stability to HER and OER.